An electric vehicle will be referred to as an “EV” hereinafter. In the present application, the EV is not necessarily a four-wheeled vehicle, and a two-wheeled vehicle and a three-wheeled vehicle are also included. A plug-in hybrid vehicle capable of being externally charged is also an EV and expected to be widespread in the future. The EV uses no fossil fuel and therefore emits no exhaust gas such as carbon dioxide. Hence, the EV is expected as a last resort for energy saving and global warming suppression. The EV is also considered to serve as a storage battery for supplying power to a home or important facility in case of power failure caused by a disaster or the like. Hence, the EV has also received attention as a new social infrastructure.
The EV uses power stored in a storage battery to run. For this reason, the user of the EV needs to charge the EV, instead of refueling a conventional gasoline-powered vehicle. However, the time necessary to charge the current EV is longer than the time needed to refuel the gasoline-powered vehicle. In addition, the distance the EV can run by one charge is shorter than the distance the gasoline-powered vehicle can run by one refueling.
If the number of EVs running in urban districts grows in the future, it is feared that charging stations will be crowded by many EVs to be charged, power to EV charging facilities such as charging stations will fall in short supply, or the batteries of the EVs will be exhausted on the road.
Especially on expressways, there are fewer locations to build charging stations than on open roads because they can be built only in limited locations such as rest areas or stops. For this reason, reducing the dependency on specific charging stations and preventing battery exhaustion on the road may be important challenges.
For open roads as well, an operation plan needs to be made in consideration of the scheduled running distance of the EV, which is affected by the amount of electricity remaining in the storage battery of the EV, the time needed for charging, a variation in the power supply amount used for charging and the like in the fields of, for example, a shared vehicle as in car sharing or car rental, public transportation such as buses and taxis, and commercial vehicles for home delivery services and the like.
Hence, there is a demand for a technique of accurately estimating the distance the EV can run on the electricity remaining in its storage battery, the charging amount necessary to reach the destination, and the like.
Each auto manufacturer provides an estimated value of the runnable distance based on the storage battery level to a driver as a function of the EV manufactured by the manufacturer or a service for the driver of the EV manufactured by the manufacturer.
For example, there is a runnable distance estimation system that determines the parameters of a power consumption model from the running history of an EV. This technique adjusts, based on the running history of each EV, the parameters of the power consumption model of the single EV and improves the consumed power amount estimation accuracy.
There also exist a navigation apparatus and a destination reachability determination method that estimate the runnable distance based on partial information. In this technique, the apparatus for estimating the runnable distance itself is installed in the EV. However, in this technique, not only internal information of the EV but also information outside the EV is input, and the runnable distance is estimated based on the input information.
As described above, to distribute the load on the charging stations and prevent battery exhaustion of the EV, a road corporation needs to predict the charging action of the driver who is driving the EV running on the road.
Even when performing operation management for shared vehicles, taxis, or commercial vehicles such as a delivery car, the operation manager needs to grasp the charging amount necessary for the EV to run and the charging time necessary to charge the EV.
For such a business application purpose, the operation or charging needs to be managed for all EVs in a situation where not only EVs of a specific auto manufacturer or a specific car model but also EVs of various car models of various auto manufacturers coexist. However, there are the following problems in the current estimation of the consumed power amounts or runnable distances of EVs of various auto manufacturers.
Note that in the description of this specification, a term “consumed power amount” and a term “power consumption” are used. “Consumed power amount” represents the amount of power consumed by the EV and is used in, for example, an expression “estimation of a consumed power amount”. “Power consumption” represents a phenomenon that the EV consumes power and is used in, for example, an expression “power consumption model”.
As the first problem, there is no mechanism that allows other corporations such as an expressway corporation and an EV service provider to use the estimated values of consumed power amounts or runnable distances of EVs of various auto manufacturers.
As the second problem, the definition and accuracy of estimated values vary between the auto manufacturers.
As the third problem, the driver cannot effectively acquire and use knowledge of external factors that affect the power consumption of the EV.
The three problems will sequentially be explained below.
The first problem will be described. Each auto manufacturer notifies, concerning only EVs produced by the auto manufacturer, the driver of each EV of the estimated value of the runnable distance based on the remaining electricity amount of the storage battery. The estimated value is notified to the driver via, for example, a user interface such as the console of the driver's seat or a car navigation device.
However, auto manufacturers have not made the estimated values of runnable distances available in a form that allows other corporations such as an expressway corporation and an EV service provider to access from a computer system. Hence, for example, even when wanting to grasp the consumed power amount or runnable distance of an EV running on an expressway, the expressway corporation cannot use the estimated value of the consumed power amount or runnable distance by the auto manufacturer under the present circumstances.
The second problem will be described. Even if auto manufacturers make the estimated values of the consumed power amounts or runnable distances of EVs available to other corporations, the estimated values are insufficient as values used by corporations such as an expressway corporation that handles the EVs of a plurality of auto manufacturers.
This is because the definition and estimation accuracy of estimated values vary between the auto manufacturers or car models, and the estimated values cannot therefore be handled by the same standard. For example, in an EV model A1 of the electric vehicle of an auto manufacturer A, a margin of about 20% may be taken into consideration for the estimated value of the runnable distance. Note that this model presents the estimated value supposing a charge of about 20% remains in the storage battery even when the EV has run the estimated distance and consumed power as estimated.
For example, in an EV model B2 of an auto manufacturer B, an error of ±10% may be taken into consideration for the estimated value of the consumed power amount. In an EV model C3 of an auto manufacturer C, errors of +5% and −30% may be taken into consideration for the estimated value of the consumed power amount.
As described above, in a situation where the definition and estimation accuracy of estimated values are not determined, even if the auto manufacturers make the estimated values available to the corporations, it is impossible to sufficiently utilize the estimated values for operation management of all EVs of the auto manufacturers.
The third problem will be described. Power consumption of the EV is affected not only by the mechanical factors (motor, battery, body shape, and the like) of the EV itself but also by factors outside the EV.
The external factors can include, for example, weather such as an atmospheric temperature and wind, road conditions such as a road surface state and a gradient, traffic conditions such as a traffic jam, and factors depending on the driver (fast start, hard braking, and the like). Since these external factors change all the time, data derived from the external factors cannot always be included in the estimated apparatus installed in the EV or an external server connected via a network.
As a method of estimating the power consumption of the EV, a method of estimating the influence of the external factors on the power consumption based on the past running history of the EV can be considered. However, the running range in the past running history of each EV is limited. In addition, the states of the external factors that occurred during running of the EV are also limited. It is therefore difficult to cope with unknown external factors.